1. Field of the Invention
The present invention relates to a recording and/or reproducing apparatus for a recording medium. More particularly, the present invention relates to a recording and/or reproducing apparatus for a recording medium, with a display unit.
2. Background of the Invention
For example, as reproducing apparatus capable of reproducing a tune, a voice or the like, there have been known reproducing apparatus for an optical disc and a magneto-optical disc, for example, a compact disc (CD), on which an audio signal is recorded as a digital signal.
In the recent years, there have been known disc recording and/or reproducing apparatus by which a user can record tune data or the like on a magneto-optical disc which is used as a recording medium. This disc recording and/or reproducing apparatus are provided with an area where data of audio data, a tune or the like has already been recorded and a data area (a user table of contents, hereinafter referred to as "U-TOC") where data for managing unrecorded area is provided. For example, the management data is rewritten in accordance with operation of recording, editing, erasing or the like.
For example, in recording a certain audio data, the recording and/or reproducing apparatus searches the unrecorded area on a disc from the U-TOC, and records audio data which has been inputted to the apparatus on that unrecorded area. In reproducing audio data, the recording and/or reproducing apparatus discriminates an area on which audio data (track) to be reproduced has been recorded from the U-TOC and accesses to that area before executing a reproduction operation.
The recordable disc media such as a magneto-optical disc allow random access to be extremely facilitated in comparison with tape-shaped recording media such as a DAT (Digital Audio tape) or a compact cassette tape. This makes it unnecessary to record from the inner peripheral side toward the outer peripheral side on the disc, that is, from a first track to an n-th track in the correct order. In other words, even though respective tunes have been recorded at the physically dispersed positions on the disc, a tune can be reproduced in the correct order as far as the addresses at the first track to the n-th track where the respective tunes have been recorded are managed.
Furthermore, the foregoing recordable disc media make it unnecessary to always record, for example, one track (audio data) on continuous parts (here, the parts mean parts where physically continuous data have been recorded), and not suffer from any problems even though audio data has been recorded discretely on a plurality of separated parts on the disc discretely.
In particular, in a recording and/or reproducing apparatus where data read out from a magneto-optical disc is stored in a buffer memory at a high rate once, and the data is then read out from the buffer memory at a low rate before the data is subjected to a demodulating process into an audio reproduction signal, even though reading data from the magneto-optical disc is interrupted temporarily due to access between the parts, the reproduced signal can be outputted without being interrupted.
Accordingly, if the recording and/or reproducing operation within the parts and the high-rate access operation (the access operation which terminates within a reproducible period of time due to a data storage quantity-produced by a difference between a writing rate and a reading rate of the buffer memory) are repeated, even though a track for one tune is separated into a plurality of parts so as to be physically divided, the recording and/or reproducing operation for the tune does not suffer from any problems.
For example, as shown in FIG. 1, a plurality of tunes have been physically continuously recorded on one part in such a manner that a first tune has been recorded on a part M.sub.1 and a second tune has been recorded on a part M.sub.2. Also, each tune can be recorded on the disc so as to be divided into a plurality of parts as shown by parts M.sub.4(1) to M.sub.4(4) and M.sub.5(1) to M.sub.5(2) provided for a fourth tune and a fifth tune, respectively. FIG. 1 simply shows a schematic example, and actually there are many cases where one part is organized by several to several hundred tracks or more.
When the operation of recording or erasing a tune with respect to a magneto-optical disc is repeated, a difference in a performance time of the recording tune or in a performance time of the erased tune causes an empty area on a track to be produced irregularly. However, the execution of such a discrete recording operation enables a tune longer than the erased tune to be recorded by utilizing its erased portion. With the repeated recording/erasing operation, the occurrence of a useless data recording area is avoided. What is recorded is not necessarily limited to "tune", but includes anything if it is of an audio signal. However, in this specification, a description will be given assuming that a tune is recorded as data (track) of one unit having continuous contents.
In the magneto-optical disc, during the recording operation, the recording operation must be continued while accessing to a plurality of parts constituting unrecorded areas. During the reproducing operation, the parts must be accessed in such a manner that one tune is continuously recorded correctly. Data necessary for joining parts (for example, M.sub.4(1) to M.sub.4(4)) together within one tune and data representative of an unrecorded area, which are required to satisfy the foregoing conditions, are recorded on the magneto-optical disc as the U-TOC information which can be rewritten every recording operation or erasing operation as described above. The recording and/or reproducing apparatus is controlled so as to perform the recording/reproducing operation appropriately by reading the U-TOC information to conduct the accessing operation of a head.
The recording data on the magnetic disc is organized by cluster unit CL (=36 sectors) unit consisting of a sub data area of 4 sectors (1 sector=2352 bytes) and a main data area of 32 sectors, and one cluster is set as a minimum unit during the recording operation. One cluster corresponds to 2 to 3 tracks. An address is recorded every sector.
The sub data area of 4 sectors is used as sub data, a linking area or the like. The TOC data, audio data or the like is recorded on the main data area of 32 sectors.
The sector is further sub-divided into a plurality of sound groups in such a manner that two sectors are divided into 11 sound groups. Within the sound group, data of 512 samples is separated into an L-channel and a R-channel and then recorded. One sound group has the quantity of audio data corresponding to a period of time of 11.6 msec.
In the foregoing reproduction of a tune or the like through a disc-shaped recording medium such as the magneto-optical disc, a current reproduction position is displayed in the time-axial manner on a display unit of the reproducing apparatus. For example, as this display technique, there has been known that a track number of a track which is now being reproduced and a reproduction elapsed time for this track are displayed by minutes/seconds. Also, there has been known that this display mode is changed over to display a reproduction remaining period of time for a track which is being reproduced. Moreover, the display mode is changed over to display a reproduction elapsed period of time, a reproduction, remaining period of time or the like relative to a total recording period of time of the magneto-optical disc.
Further, in the case of recording a tune as audio data or the like on the disc-shaped recording medium, there has been known a display system such that, in the recording standby state or the like, the number of recording tracks, for example, a recorded period of time, a recordable remaining period of time and the like are calculated frown the U-TOC information and then displayed, and during the recording operation, a track number of a track which is now being recorded, a recording position on that track, and the like are displayed by minutes/seconds.
However, the foregoing display system suffers from a problem, for example, that, because an elapsed period of time for a certain track is displayed only by a numerical display, this makes it difficult for a user to instantaneously grasp where is factually a reproduction position or a recording position on the whole magneto-optical disc as a disc-shaped recording medium.
In particular, in the foregoing recording and/or reproducing apparatus using the buffer memory, there has been known a recording system in which an unrecorded area (free area) on which a tune has not been recorded as data is automatically searched to execute recording, as well as a so-called over-write recording system in which past data is erased from a portion at which the recording operation starts, that is, a past tune is erased in the same manner as that in using the compact cassette tape, and a new tune is recorded thereon. However, in the case of recording on the magneto-optical disc through the over-write recording system, if the user relies on the foregoing position displaying by only the numerical display, he cannot instantaneously grasp where is a position at which recording is to start on the whole magneto-optical disc, and is liable to feel uneasy whether the current recording start position actually coincides with a position that the user desires or not.
Further, one type of the foregoing recording and/or reproducing apparatus using the buffer memory is provided with a resume function. The resume function is so designed that even though a reproducing operation is stopped or a power supply is turned off by operating a stop key or a power key, a final reproduction stop position is stored and held as a resume point so far as the magneto-optical disc remains loaded without being ejected. Thereafter, for example, in the case where the power supply is again turned on to conduct reproduction or recording (in this case, the foregoingover-write system), the resume point can be set to a recording/reproducing start position. In this case, similarly, a position on the whole magneto-optical disc to be reproduced or recorded is difficult to instantaneously grasp particularly due to the position displaying by only numerical display.